Article info Vol. 6  No. 4   pp.  96 ~ 99
Title Purification and preliminary analysis of the ATP-dependent unfoldase HslU from the gram-positive bacterium Staphylococcus aureus
Authors Soyeon Jeong1, Nam-Chul Ha1,* and Ae-Ran Kwon2,*
Institutions 1Research Institute for Agriculture and Life Sciences, Center for Food and Bioconvergence, Center for Food Safety and Toxicology, Seoul National University, Seoul 08826, Republic of Korea, 2Department of Herbal Skin Care, College of Herbal Bio-industry, Deagu Haany University, Gyeongsan, Gyeongbuk 38610, Republic of Korea *Correspondence: hanc210@snu.ac.kr, arkwon@dhu.ac.kr
Abstract The gram-positive bacterium Staphylococcus aureus is a common cause of abscesses, sinusitis and food poisoning. The emergence of antibiotic-resistant strains has caused significant clinical issues worldwide. The HslU-HslV complex was first identified as a prokaryotic homolog of eukaryotic proteasomes. HslU is an unfoldase that mediates the unfolding of the substrate proteins, and it works with the protease HslV in the complex. To date, the protein complex has been mostly studied in gram-negative bacteria. In this study, we report the purification and crystallization of the full-length HslU from S. aureus. The crystal diffracted X-rays to a 3.5 Å resolution, revealing that the crystals belong to space group P21, with unit cell parameters of a = 166.5, b = 189.6, c = 226.6 Å, and β = 108.1°. We solved the phage problem by molecular replacement using the structure of HslU from Haemophilus influenzae as a search model. The cell content analysis with this molecular replacement solution revealed that 24 molecules are contained in the asymmetric unit. This structure provides insight into the structural and mechanistic difference of the HslUV complex of gram-positive bacteria.